Back to results
US 4,376,289 AGranted
Self-enabling dropout corrector
AssigneeRCA Corporation
InventorsGlenn A. Reitmeier, Frank J. Marlowe
Life of this patent
Estimating the term…
Abstract
A dropout compensator includes an estimator for forming continuous estimates of the value of a video signal subject to dropouts. In order to determine the presence of a dropout, the estimated signal is compared with the actual signal to form a difference. When the difference exceeds a predetermined amount, the estimated value is substituted for the actual value.
Claims11
A television dropout compensator for video signals from a source of video signals which video signals are subject to dropouts, comprising:
- estimating means coupled to the source of video signals for forming an estimated signal representing an estimate of the value of each pixel of said video signals;
- comparison means coupled to said estimating means and to said source of signals for comparing each pixel of said video signal with the corresponding estimated signal for generating an error signal representative of the difference therebetween;
- threshold means coupled to said comparison means for comparing said error signal with a reference value and for generating a dropout signal when said error signal exceeds said reference value;
- and
- gating means coupled to said threshold means, to said source of signals and to said estimating means for coupling said estimating means to an output terminal of the dropout compensator in response to said dropout signal.
2 more elements
A method of compensating for dropouts in a video signal, comprising:
- making an estimate of the value of the video signal;
- comparing said estimated value of the video signal with said video signal for obtaining a difference signal indicative of the difference therebetween;
- determining whether the magnitude of said difference signal is greater than or less than a predetermined magnitude;
- and
- substituting for said video signal said estimated value of the video signal when the determination is that said difference signal exceeds said predetermined magnitude.
2 more elements
A method of detecting dropouts in a video signal, comprising:
- making an estimate of the value of the video signal;
- comparing said estimated value of the video signal with said video signal for obtaining a difference signal indicative of the difference therebetween;
- and
- establishing the presence of a dropout by determining if the magnitude of said difference signal is greater than a threshold.
1 more element
A television dropout compensator for video signals from a source of video signals which video signals are subject to dropouts, comprising:
- adaptive estimating means for producing an estimated signal representing the value of a pixel of said video signals, said adaptive estimating means comprising:
- delay means for providing pixel amplitude signals from pixels preceding and following a currently processed pixel;
- first averaging means coupled to said delay means for producing a first estimate of the value of said currently processed pixel by processing pixels from horizontal lines preceding and following the line containing said currently processed pixel;
- second averaging means coupled to said delay means for producing a second estimate of the value of said currently processed pixel by processing pixels preceding and following said currently processed pixel on said line containing said currently processed pixel;
- absolute-value means coupled to said delay means for producing first and second signals representative of the magnitude of the rate of change of the values of the pixels in first and second directions, respectively;
- comparison means coupled to said absolute-value means for generating a control signal indicative of the one of said first and second signals having the least magnitude;
- and
- gating means coupled to said first and second averaging means and to said comparison means for gating to an output terminal of said adaptive estimating means one of said first and second estimates under the control of said control signal for forming said estimated signal;
- said television dropout compensator further comprising:
- second comparison means coupled to said adaptive estimating means and to said source of video signals for comparing each pixel of said video signal with the corresponding pixel of said estimated signal for generating an error signal representative of the difference therebetween;
- threshold means coupled to said second comparison means for comparing said error signal with a reference value and for generating a dropout signal when said error signal exceeds said reference value;
- and
- gating means coupled to said threshold means, to said source of video signals and to said adaptive estimating means for coupling said estimated signal to an output terminal of said dropout compensator in response to said dropout signal.
10 more elements
Dependencies are inferred from the claim text.